CFD simulation of turbulent flow in a rod bundle with spacer grids (MATIS-H) using STAR-CCM

• Published in: Nuclear engineering and design 2014-11, Vol.279, p.37-49
• Main Authors: Cinosi, N., Walker, S.P., Bluck, M.J., Issa, R.
• Format: Article
• Language: English
• Subjects: Bundling; Computational fluid dynamics; Computer simulation; Mathematical models; Spacers; Turbulence; Turbulent flow; Vorticity
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2014.06.019

•CDF simulation of turbulent flow generated by a typical PWR spacer grid.•Benchmarking against the MATIS-H experiments run at KAERI in Daejeon, Korea.•Deployment of various steady RANS models to compute the turbulence.•Sensitivity analysis of hardware components. This paper presents the CFD simulation of the turbulent flow generated by a model PWR spacer grid within a rod bundle. The investigation was part of the MATIS-H benchmark exercise, organized by the OECD-NEA, with measurements performed at the KAERI facilities in Daejeon, Korea. The study employed the CD-Adapco code Star-CCM+. An initial sensitivity study was conducted to attempt to assess the importance to the overall flow of components such as the outlet plenum and the end support grid; these were shown to be able to be safely neglected, but the tapered end portion of the rods was found to be significant, and this was incorporated in the model analyzed. A RANS model using any of K-epsilon, K-omega and Reynolds-stress turbulence models was found to be adequate for the prediction of mean velocity profiles, but they all three underestimate the time-averaged turbulent velocity components. Vorticity seems to be better predicted, although the measured values of vorticity are only presented via colored contour plots, making quantitative comparison rather difficult. Circulation, calculated via an integral for each channel, seems to be well predicted by all three models.